The invention is based on a valve as generically defined by the preamble to the independent claim.
Such valves are known, for instance from German Patent Disclosure DE 197 53 575 A1. The valve described in DE 197 53 575 A1 is a magnetic bypass valve for a liquid-regulated heating or cooling system. Two valve members secured to a lifting rod of the valve regulate the flow between an inlet conduit and two outlet conduits, and one of these outlet conduits takes on the function of a bypass conduit in the heating and cooling cycle. A disadvantage of the valve described in DE 197 53 575 A1 and of all comparable valves isxe2x80x94for reasons of constructionxe2x80x94the quite complex assembly of the individual components of the valve. First the sealing rings, which form the valve seats of the valve chamber, and a spacer sleeve that defines the actual valve chamber of the valve have to be thrust onto the lifting rod of the valve. After that, a first valve member, the bypass valve member, can be mounted on the lifting rod and secured to the lifting rod with a securing shim. This preassembled unit comprising the lifting rod, bypass valve member, valve seats and spacer element is thrust into the valve housing, and the individual components are placed in their position. After that, a further spacer sleeve for affixing the valve chamber must be introduced into the valve housing, and only after that can the second valve member, for monitoring the useful outlet, be secured to the lifting rod.
This described assembly is inconvenient, complicated and thus expensive. Furthermore, the fastening of the valve members to the lifting rod must be secured in a complicated way by means of a groove in the lifting rod and one additional securing shim.
The valve according to the invention having the characteristics of the main claim has the advantage of enabling faster, better assembly in the manufacture of valves. The sequence of assembly becomes virtually independent of the instant of installation of the lifting rod in the valve housing, since the lifting rod, with the valve members fixedly mounted on it, can even be introduced later on into the valve chamber. An elastic stretchability of the sealing elements, that is, of the valve seat and/or valve member, assures that the valve member can be led through the applicable valve seat by some exertion of force from outside, and when the valve is in operation the sealing elements have by then resumed their original shape, so that the valve chamber is securely sealed off in the desired way. The requisite force expenditure for pressing the valve member through a valve seat can be exerted from outside; however, it is also conceivable for this expenditure of force to be brought to bear by actuators, optionally triggered in an amplified way, that cooperate with the valve members.
By the provisions recited in the other claims, advantageous refinements of and improvements to the valve defined by claim 1 are possible.
Suitably shaped valve members and valve seats make it possible to press the lifting rod through the valve chamber more easily. By the embodiment of a chamfer on the side of the valve member remote from the associated valve seat, which side extends relative to the axis of the lifting rod, and a corresponding chamfer of the same inclination on the side of the associated valve seat remote from the valve member, it is attained that the valve member can be passed more easily through the valve seat.
Material comprising the valve seat or the valve member can be received during the passing of the valve member through the valve seat in recesses embodied in the lifting rod, valve member or the associated valve seat, thus making it easier to pass the valve member through the valve seat. In valve operation, the sealing elements have resumed their original shape, so that the valve chamber is securely sealed off in the desired way.
It is also possible, by means of a chemical treatment of the sealing surfaces of the valve member and valve seat with a lubricant, to minimize a sliding friction that occurs while the valve member is being passed through the valve seat.
The valve according to the invention in particular enables preassembly of the valve chamber of valves, of the type described in DE 197 53 575 A1: The sealing rings, which form the valve seats, and the spacer sleeve that embodies the actual valve chamber can already be installed in the valve housing before the lifting rod is installed.
Only the valve members are mounted on the lifting rod itself. The valve members are press-fitted, for example, onto the lifting rod as they always have, at the desired point, and are optionally additionally calked for the sake of security with material comprising the lifting rod. The calking offers a simple, reliable way of securing the valve members to the lifting rod. The lifting rod thus mounted outside the valve housing, with its valve members secured to it, can then be inserted through the valve chamber into the preassembled valve housing, because of the elasticity of the valve seat and the valve member.
The lifting rod of the valve of the invention can be produced for example from a plastic as well. This lowers the cost for material on the one hand and on the other has the advantage that the valve members can be welded directly into the lifting rod, which in turn means a substantial simplification in assembling the valves.
The valve of the invention thus makes a modified, faster assembly possible and thus results in improved quantity and reduced costs in the production of the valve.